New device could contribute to a major increase in the rate of future optical communications — phys.org

This illustration (not to scale) simulates the process by which an incoming complex wave can be identified and transmitted to a photodetector. Credit: Image courtesy of Patrice Genevet.

New device could contribute to a major increase in the rate of future optical communications

January 8, 2013

(Phys.org)—At a time when communication networks are scrambling for ways to transmit more data over limited bandwidth, a type of twisted light wave is gaining new attention. Called an optical vortex or vortex beam, this complex beam resembles a corkscrew, with waves that rotate as they travel.

Now, applied physicists at the Harvard School of Engineering and Applied Sciences (SEAS) have created a new device that enables a conventional optical detector (which would normally only measure the light’s intensity) to pick up on that rotation.

The device, described in the journal Nature Communications, has the potential to add capacity to future optical communications networks.

“Sophisticated optical detectors for vortex beams have been developed before, but they have always been complex, expensive, and bulky,” says principal investigator Federico Capasso, Robert L. Wallace Professor of Applied Physics and Vinton Hayes Senior Research Fellow in Electrical Engineering.